Alerting: Integrations in contact point executed with offset

### What happened? I'm running two instances of Grafana as HA peers for alerting. I have a contact point which has 3 different integrations, 1 of type Email and 2 of type Webhook. The second webhook integration has been added later on. <img width="673" height="243" alt="Image" src="https://github.com/user-attachments/assets/d84d3c65-a386-46a0-8b24-38add338be50" /> I'm experiencing now with one specific alert that it seems to be evaluated twice with a small offset in time. The first two integrations (1 email & 1 webhook) are sent at the same time. With an offset of 41min the second webhook is triggered. This is only the case for one specific alert. This alert has 530 series and is evaluated every 30 seconds. Yes, I tried to turn it off and on again.😁 Tried to restart the Grafana instances one after another, but this didn't resolve the issue. ### What did you expect to happen? I'm expecting that the integrations for one contact point are triggers simultaneously. ### Did this work before? Since I've added the third integration (Second of same type as one existing) it's happening. I had not this particular case before. ### How do we reproduce it? 1.Don't know how to reproduce. Issue is happening since I've added the third integration (second webhook). 2. 3. ### Is the bug inside a dashboard panel? No ### Environment (with versions)? Grafana: OSS 12.3.1 OS: RHEL 9.7 Browser: not used for this issue. ### Grafana platform? A downloaded binary ### Datasource(s)? Prometheus